1. Field of the Invention
The present invention relates to a semiconductor device, a process for production thereof, and a surface-protecting film. More particularly, the present invention relates to a resin-sealed semiconductor device obtained by resin-sealing a semiconductor element whose surface is coated with a polyimide, a process for production thereof, and a surface-protecting film suitable for protection of a semiconductor element.
2. Description of the Related Art
In the conventional production of a resin-sealed semiconductor device, it is conducted, for the surface protection of semiconductor element or for the prevention of semiconductor element malfunctioning caused by the .alpha.-ray emitted from sealing resin, to form a surface-protecting film of a polyimide resin on the surface of a semiconductor element and then conduct sealing with a molding resin.
Mounting of such a resin-sealed semiconductor device is now conducted mainly by surface mounting. In the surface mounting, the leads of semiconductor device and the wires of printed wiring board are temporarily connected, and the semiconductor device and the wiring board are heated to conduct soldering. The heating is conducted mainly by a method of using a radiant heat of infrared rays (infrared reflowing) or a method of using a condensation heat of fluorine-based inert fluid (vapor phase reflowing).
In such surface mounting, it occurs in some cases that the water absorbed inside a resin-sealed semiconductor device is rapidly vaporized by the heat applied during soldering and the resulting vapor pressure allows the sealing member (resin) of said device to generate cracking. This cracking poses a serious problem with respect to the reliability of semiconductor device [Transactions of the Japan Society of Mechanical Engineers (A), 55 (510), 356-363 (1989)].